This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 12 |
| 3 | 21 |
| 4 | 30 |
| 5 | 102 |
| 6 | 111 |
| 7 | 120 |
| 8 | 201 |
| 9 | 210 |
| 10 | 300 |
| 11 | 1002 |
| 12 | 1011 |
| 13 | 1020 |
| 14 | 1101 |
| 15 | 1110 |
| 16 | 1200 |
| 17 | 2001 |
| 18 | 2010 |
| 19 | 2100 |
| 20 | 3000 |
| 21 | 10002 |
| 22 | 10011 |
| 23 | 10020 |
| 24 | 10101 |
| 25 | 10110 |
| 26 | 10200 |
| 27 | 11001 |
| 28 | 11010 |
| 29 | 11100 |
| 30 | 12000 |
| 31 | 20001 |
| 32 | 20010 |
| 33 | 20100 |
| 34 | 21000 |
| 35 | 30000 |
| 36 | 100002 |
| 37 | 100011 |
| 38 | 100020 |
| 39 | 100101 |